Rotary-piston packing



W. G. E. ROLAFF.

ROTARY PISTON PACKING.

APPLICATION FILED AUG.4. I9I9.

l 1,358, 1 76, Patented Nov. 9,'1920.

UNITED .STATES WALTER Gr. E. RQLAFF, 0F BELLEVILLE, ILLINOIS.

ROTARY-PISTON PACKING.

Application filed August 4, 1919.

To LIZ whom t may concer/n Be it known that I, XVALTER Gr. E. Ro- LAFF, a citizen of the United States, residing at Belleville,. in the county of St. Clair and State of Illinois, have invented new and useful Improvements in Rotary- Piston Packing, of which the following is a specification.

This invention relates to rotary machines, such as air compressors, rotary engines, pumps. or any other rotary machine operating with a fluid. The invention is particularly applicable to rotary machines of the type in which a drum, o1' rotor, rotates within a barrel or cylinder and carries a piston which touches the inner face of the cylindrical shell and the heads.` It is necessary to provide means for packing the piston in order to prevent leakage. The line of con- Ytact of thepiston with the shell may be packed very\readily, but it is more difficult to pack the ends of the piston where they touch the heads of the barrel.

The general object of the present invention is to provide improved means for packing a rotary machine of this type. ln one aspect, the invention may be regarded as an improvement of the rotary piston packing disclosed in my Patent No. 1,280,309, dated October 1, 1918. The packing means disclosed in (the patent referred to above involves the use of over-lapping plates, which by reason of this construction were made relatively thin. As these relatively thin plates project at times a considerable distance past the periphery of the drum, an element of weakness is present in such a construction; one ofthe objects of the present invention is to overcome this defect and to provide a rotary piston packing of simple construction which will operate effectively to insure effective packing of the piston at the heads of the barrel without necessitating the weakening of the packing means or plates by reducing their thickness as referred to above.

My invention operates in such a way that I utilize the relatively high Huid pressure existing within the rotary machine to press the packing membersof the piston firmly against the heads.

Further objects of the invention will appear hereinafter.

The invention consists in the novel features, and in the general combination of parts to be particularly described herein- Specification of Letters Patent.

Patented Novya, i920.`

Serial N0. 315,191.

after, all of which contribute to produce a simple and efficient rotary piston packing. A preferred embodiment of my invention will be particularly described in the following specification, while the broad scope of my invention will be pointed out in the appended claims.v

In the drawing,

Figure 1 is a vertical cross-section through a rotary machine embodying my invention;

Fig. 2 is a longitudinal vertical section;

Fig. 3 is a horizontal cross-section on the line 3 3 of Fig. 2, and

Fig. 4 is a rear elevation showing details of the construction.

The rotary machine to which I have illustrated my invention as applied, comprises a' barrel having a cylindrical shell 1, and substantially fiat heads 2; within this barrel there is rotatably mounted a drum 3, carried by a shaft 4, which cooperates with the barrel to form a chamber 5; in the present instance this chamber is formed by mounting the drum eccentrically in the barrel in a well known manner. The drum carries a piston 6 which is preferably of blade form, having means so constructed that when acted upon -by the fluid pressure on the working side of the piston, the force exerted by the fluid under pressure will press the packing members against the heads. In order to accomplish this, I prefer to construct piston blade 6 with a main plate, or section 8 disposed between packing members 0r plates 7 disposed respectively adjacent to each head 2.

This plate and the packing members 7 are mounted to slide freely in and out in a piston guide-opening 9, which is formed substantially radially in the drum. The direction of rotation of the drum is indicated by the arrows in Figs. 1 and 3, so that the forward lateral face or side 10 of the piston 6,

bers 7 out against the heads 2. I accomplish this in a very simple manner, preferably by constructing the piston blade 6 in such a way that the main plate or main section 8, and the packing members are so correlated that the main plate will operate as a wedge plate, that'is to say, it reacts against the pressure of the packing members 7 and forces the packing members outwardly; for this purpose the Vpacking y member 7 and the plate 8 are provided .with meeting faces 11, which are inclined with respect to the plane of the blade, that is to say, they lie in a plane passing from the forward or working side of tlie blade to the rear side of the blade (see Fig. 3) in this way, the packing members form a flexible scarf-joint or sliding joint with the main plate. As the meeting faces are thoroughly oiled, it is evident that when the relatively high fluid pressure in the chamber 5 exerts itself on the working side`of the blade, that is to say, .upon the working side` of the packing members 7, they will tend to slide in an outward direction on account of the inclination of the faces 11; in doing this, the plate 8 will act as a reaction wedge, as it were.

In order to insure efficient operation of the piston blade 6, and also to prevent the packing members 7 from slipping out by themselves under the action of the centrifugal force, in case the main plate should stlck and not move outwardly when it should, I prefer to provide means for limit- 4ing the movement of the packing members with respect to the main plate. This means permits'a limited amount of movement only and` preferably consists of a pin 12 corresponding to each packingmember carried by the l slightly enlarged opening 13 in the corresponding packing member.

The direction of rotation is indicated by the arrows xin Figs. 1 and 3. These rotary machines run at a relatively high speed, so that the centrifugal force acting upon the blade 6, will insure efficient packing of the outer edge of the blade, that is to say, it will pack the line of contact between the blade and the shell. By reason'of the incllned faces 11, the packing members will also pack the line of contact between the .endslof the blade and the heads 2.

Referring to Fig. l, which illustrates the inventlon as applied to a compressor, it will be evident that as the piston blade 'traverses the chamber 5, it will `'produce a artial vacuum behind it, drawing inthe air at the inlet 14, which will be compressed in front of the piston which will nally force the air out throughthe outlet valve l14:" from which the compressed air will pass to a suitable accumulator or reservoir.

I provide means for eliminating 'the compression of the fluid, or air, which might take place at the inner end of the guideopening 9, and 'I also provide means for balancingor counter-balancing the pressure of the lluidonthe working face and rear i y face of the blade lying withinthe guideopening 9. In order to accomplish this,.I construct thev blade and the drum in'such plate 8, said pin projecting into a a way that they will coperate to admit the fluid under pressure from thel chamber 5 adjacent to the working side 10 of the blade, into the inner end of the guide-opening 9. In order to accomplish this, I simply provide a plurality of small grooves l5, which I cutl in the forward face ofthe guideopening, (with respect to the direction of rotation), and I also provide an equalizing chamber 16 on the rear side of the blade. This is formed by cutting a recess in the rear face of the guide-opening and providing communication between this equalizing chamber and the inner end of the guideopening. I also prefer to .provide a wide rectangular shallow channel 17 in the rear side of the blade, that is, in the main plate the equalizing chamber 16 and also results in producing a wearing rib 18 at the inner end of the plate which bears against the rear face of the guide-opening 9. Through thisrib 18, I cuta recess, or notch 19, which maintains constant communication, between the inner end of the guide opening 9 and the equalizing chamber. 'If desired, may also provide an opening 20 through this plate which opens communication between the air films on the opposite sides of thc plate 8 in the guide-opening.

With this organization of parts, it is evident that the relatively high fluid pressure which is developed on the working .side of the blade, will be admitted to both sure forces 'actingon these two faces are substantially equalized. There is however,

' a slight excess of force on the working side lfaces of the piston blade so that the pres- 'I the equalizing chamber to prevent escape.

of the fluid under pressure to the portion of the chamber 5 which lies adjacent to the rear side of the blade, I provide a wear-strip 21 whichis preferably ormed of hardened steel and whlch is counter-sunk in the face of the guide-opening.

When this piston packing is employed on I a rotary steam engine instead of on a compressor, of course the working.side'of the blade would be the rear side instead of the forward side, as in a compressor. However, in either case, I `utilize the working pressure exerted upon the side face of the blade to effect the holdingof the packing members against the heads ofthe cylinder.l

It is understood that the embodiment of the invention described herein is only one of the man embodiments my invention may take, and do not wish to b e limited in the 'practice of my invention nor 1n my claims,

to the particular embodiment set forth.`

What claim and desire'to secure by Letters Patent is:

l. ln a rotary machine operating with a fluid, the combination of a barrel having a cylindrical shell, and heads, a drum rotat ably mounted within the b arrel and coperating therewith to form a chamber, a pis-y ton blade carried by the drum and traversing said chamber so that a relatively high fluid pressure is developed in the latter on nthe lateral face of the blade, said blade including a packing member disposed against each head, and including means whereby the fluid pressure exerted upon the said lateral face of the blade forces the packing members against said heads.

2. In a rotary machine operating with a fluid, the combination of a barrel having a cylindrical shell, and heads, a drum rotatably mounted within said barrel and coperating therewith to form a chamber, a piston blade carried by the drum and traversing the chamber so that a relatively high A fluid pressure is developed in the latter on the lateral face of blade, said blade including a packing member disposed against each head and a wedge plate engaging the packing members, and reacting under the action of the fluid pressure exerted against the side of the blade toforce the packing members against the heads. l

3. n a rotary machine operating with a fluid, the combination of a barrel having a cylindrical shell, and heads, a drum rotatably mounted within the barrel and coperating therewith to form a chamber, a piston blade carried by said drum and traversing said chamber so that a relatively high fluid pressure is developed in the chamber on the working side of the blade, said blade including a packing plate disposed against each head and a plate between said packing plates, said last named plate and said packing plates having meeting faces disposed in a plane inclined to the middle plane of said blade, whereby, the fluid pressure exerted upon the forward side of said packing plates operates to force the packing plates against the heads.

4. In a rotary machine operating with a fluid, the combination of a barrel having a cylindrical shell, and heads, a drum rotatably mounted within said barrel and coperating therewith to form a chamber, a piston blade carried by said drum and traversing the chamber so that a relatively high fluid pressure is developed in the latter on the work ing side of the blade, said blade including a packing plate disposed against each head and a main plate disposed between said.

packing plates, said main plate andthe packing plates having meeting faces disposed in a plane inclined to the middle plane of the blade and passing from the driving side to the rear side of said blade, said plates coperating under the action of said yHuid pressure exerted `against the side thereof to force the. packing plates against said heads.

5. A rotary machine constructed as specified in claim l, in combination with means vfor limiting the movement of said packing members.

6. A rotary machine constructed as specified in claim 2, in combination with means for limiting the movement of said packing members with respect to the wedge plate.

7 ln a rotary machine operating with a fluid, the combination of a barrel having a cylindrical shell, and heads, a drum rotatably mounted within said barrel and coperating therewith to form a chamber, a blade Icarried by said drum and movable in and out to maintain contact with said cylindrical shell and traversing said chamber so that a relatively high Huid pressure is developed in said chamber on the forward side of said blade, with respect to the direction of rotation, said blade including a packing member disposed against each head and including means whereby the said Huid pressure acting upon the forward side .of said packing'members forces the said members against said heads, and means for admitting the fluid under pressure to -the rear` sideof the blade within the drum to counter-balance the force of the fluid pressure acting on the forward side of the blade.

8. In a rotary machine operating`with a fluid, the combination of a barrel having a cylindrical shell, and heads, a drum rotatably mounted within said barrel andcoiperating therewith to form a chamber, said drum having a piston blade guide-opening, a piston blade carried by said drum and movable in and out in said guide-opening to maintain contact with said cylindrical shell, and traversing said chamber so that a relatively high fluid pressure is developed in said chamber on .the forward side of said blade with respect to the direction of rotation, said blade including a packing member disposed against each head and including means whereby the fluid pressure acting upon the forward side of said packing members'forces -the packing members against the heads, the wall of said guide-opening iis having an equalizing chamber adjacentv the rear side of said blade, and means for admitting the fluid under pressure to -the said equalizing chamber to counter-balance the force of the fluid pressure acting on the forward side of the blade.

9. ln a rotary machine operating with a i -fluid, vthe combination of a barrel having a cylindrical shell and heads, a drum rotatably mounted within said barrel and coperating therewith to form a chamber, said drum having. a piston guide-opening, a piston blade carried in said guide-opening and movablein and out therein to maintain contact, with saidv shell and 'traversing said chamber so that a relatively high fluid pressure is developed in said chamber on the forward side of blade, with respect to the direction of rotation and including a packing member disposed against each head, and also including means whereby the said fluid pressure exerted upon the forward side of said packing members forces the packing members against said heads, said guideopening and said blade being constructed so that they coperate to admlt the relatively high iiuid pressure to both sides of said blade within said guide-opening and thereby substantially balance the forces acting on the opposite sides of said blade.

10.` In a rotary machine operating with a fluid, the combination of a barrel having a cylindrical shell and heads, a drum rota- `tably mounted within said barrel and coperating therewith to form a chamber, a piston blade carried by said drum and movable in and out to maintain contact with said i cylindrical shell and traversing said chamber so that a relatively high fluid pressure is developed in said chamber on the forward side of the blade, said blade with respect to the direction of rotation including a packing member disposed against each head and including means whereby said fluid pressure exerted upon the working side of said members forces the said packing -members against the heads, the said drum having a guide-opening in which said blade moves, the inner end of said guide-opening being in communication with the interior of the chamber adjacent to the forward side of said blade to eliminate compression therein my hand.

during the inward movement of said blade, said guide-opening also having an equalizin chamber on the rear side of said blade, said blade and drum cooperating to admit the fluid under pressure to the said equalizing chamber and to the forward side of the blade within said guide-opening whereby the pressure forces acting upon opposite sides of said blade within said guide-opening are substantially balanced.

11. In a rotarymachine operating with a iiuid, the combination of a barrel having a cylindrical shell, and heads, a drum rotatably mounted within said barrel and coperating therewith to form a chamber, a piston blade carried by said drum and traversing said chamber so that a relatively high fluid pressure is developed in' said chamber on the working side of the blade, said piston blade including a packing member disposed against each head and a plate having a fiexible scarf joint with each of said packing-members, and operating as a wedge under the action of the said fluid pressure upon the driving side of .the packing members to force said packing members against said heads.

l2. A rotary machine constructed as speciied in claim 4, in combination with a pin carried b said main plate corresponding to each o said packing plates, each of said packing plates having an enlarged opening receiving its corresponding pin and permit-f ting a limited movement of said packing plates relatively to said main plate.

In testimony whereof, I have hereunto set ,WALTER G. E. ROLAFF. 

